1. Field of the Invention
The present invention relates to a transglycosylation method, a glycosidase having transglycosylation activity and applications thereof.
2. Description of the Related Art
Endo-α-N-acetylgalactosaminidase (hereinafter, “Endo-α” or “Endo-α-GalNAc-ase”) is an enzyme which recognizes a core 1 structure of an O-linked sugar chain in glycoprotein, that is, a structure having a galactosylβ1→3N-acetylgalactosamine (hereinafter, “Galβ1-3GalNAc”) disaccharide bound at the α-position to serine or threonine, and which releases the disaccharide unit by hydrolysis. The O-linked sugar chain is also called a mucin-type sugar chain and is contained in a large amount in mucin with which the surfaces of animal digestive tracts and organs are covered.
It has been reported that Endo-α producing bacteria are found in a culture of, for example, Diplococcus pneumoniae and bacteria belonging to the genus Clostridium (for example, Bhavanandan, V. P. et al., Biochem. Biophys. Res. Commum., 70, 738-745 (1976)). It has also been reported that in some Endo-α studied up to now, there is a transglycosylation activity of transferring and adding a disaccharide to an entering suitable acceptor in place of a water molecule upon hydrolysis (For example, Bardales, R. M. and Bhavanandan, V. P., J. Biol. Chem., 264, 19893-19897 (1989)). Among microorganisms known as the Endo-α-producing bacteria, there are microorganisms whose total genome sequence has been clarified.
The presence of the Endo-α-producing microorganism is known, but there is no report on the cloning of a gene for an enzyme having the Endo-α activity. That is, the amino acid sequence of the Endo-α is not revealed, and which gene is a gene encoding the Endo-α has not been specified.